What are the important meta tags I must put in my website? [closed]

There seems to be huge number of meta tags you can set. I'm guessing that some of them are more important than others.

What are the most important metatags to supply and why?

Do I even need meta tags? (looking at the stackoverflow homepage there are none)

Solution 1:

I realize this question is old, but it's still a top google hit, so I thought I would give an updated answer that includes popular social media sites.

I generally have four groups of meta info:

Regular Meta Info - used by search engines and browsers

<title>{{pageTitle}}</title>
<meta charset="utf-8"><!-- html5 version of http-equiv="Content-Type"... -->
<meta name="description" content="{{description}}">
<meta name="keywords" content="{{keywords}}">
<link rel="author" href="https://plus.google.com/{{googlePlusId}}" />
<link rel="canonical" href="{{pageUrl}}" />

Facebook Meta Info - used by Facebook when someone shares your url

<meta property="og:url" content="{{pageUrl}}">
<meta property="og:image" content="{{imageUrl}}">
<meta property="og:description" content="{{description}}">
<meta property="og:title" content="{{pageTitle}}">
<meta property="og:site_name" content="{{siteTitle}}">
<meta property="og:see_also" content="{{homepageUrl}}">

Google+ Meta Info - used by Google+ when someone shares your url

<meta itemprop="name" content="{{pageTitle}}">
<meta itemprop="description" content="{{description}}">
<meta itemprop="image" content="{{imageUrl}}">

Note: you don't really need these, Google+ will fall back to the Open Graph tags that Facebook uses.

Twitter Meta Info - used by Twitter when someone shares your url

<meta name="twitter:card" content="summary">
<meta name="twitter:url" content="{{pageUrl}}">
<meta name="twitter:title" content="{{pageTitle}}">
<meta name="twitter:description" content="{{description}}">
<meta name="twitter:image" content="{{imageUrl}}">

Solution 2:

I'll use my same answer from this question:

A few years back, meta tags were important to search engine optimization. However, they've been abused and are generally ignored by almost all search engines (including Google, Yahoo and Live search. Excuse me: Bing).

The most important tags for SEO that you can include in your (X)HTML are the <title> and <meta name="description"...> tags.

• <title> should generally be what you'd want the search engine to name your page in it's listing.
• <meta name="description"...> can sometimes give the search engine a basic idea of how to describe your page when indexing it.

However, using these two tags will not necessarily make a difference in increasing your site's visibility on a search engines listings. For more information on that aspect, Google has a nice section on SEO on their site.

Solution 3:

Update May 2015: Still being a very popular answer, I recommend you look at @alden's answer as it is much more updated then my own (6 years old now)

Original answer follows:

<META HTTP-EQUIV="Content-Type" CONTENT="text/html; charset=utf-8"> 

To tell the browser what the content type and encoding is

<meta NAME="ROBOTS" CONTENT="NOODP">

See http://www.mattcutts.com/blog/google-supports-meta-noodp-tag/ for why

<meta name="description"...>

Obvious

<meta name="keywords"...>

Google do not use this, but other search engines may

<meta HTTP-EQUIV="Expires" CONTENT="Tue, 20 Jun 1995 04:13:09 GMT">

If you know when you like this page to be expired from cache